The present invention relates to a coupling for transmitting rotary motion. More specifically, the present invention relates to such a coupling which may be quickly disconnected and reconnected by a manual operation.
Numerous forms of couplings for transmitting rotary motion are known. Common types of couplings used to join two shafts at adjacent ends include bellows couplings, sleeve couplings, flexible couplings, oldham couplings, wafer spring couplings and universal lateral couplings. If such a coupling is used to transmit a rotary motion, especially at relatively high rpm or with a high speed reciprocating motion, the ends of the shafts are held together by bolts, set screws, clamps, roll pins or rivets, to ensure that the two parts are held tightly together and that the rotary force is transmitted. These various means for holding the shafts together, however, make it necessary to use a tool such as a wrench to assemble and disassemble the coupling.
U.S. Pat. No. 3,611,748 discusses one technique for providing a coupling which may be more easily connected and disconnected. In this coupling, a spring loaded ball is used. Other similar couplings use spring clips, fast threaded devices, interference fits and similar means to allow connection and disconnection. Such means, however, are not suitable for high speed reciprocating motion and cannot withstand the accompanying vibrations.
In some applications, it is desirable to have a coupling for high speed reciprocating rotary motion which can be quickly disconnected and reconnected manually without the use of a tool. For example, it may be desired to drive any of several implements using a single driving unit. One example is small laboratory mixers and shakers such as the Vortex Genie.TM. Vortex Mixer manufactured by Scientific Industries, Inc., the assignee of the present invention. The drive unit of such a mixer may be used with any of several mixing heads, and the mixing head is a structure which holds one or more liquid containing vessels such as test tubes, beakers, flasks and so forth on the drive shaft of the mixer. These heads, which may be designed to hold a specific type of liquid containing vessel, have conventionally been marketed either as dedicated parts integral with the mixer or as add-on attachments which must be attached with a tool to a mixer drive. It is often desirable, however, to interchange heads on the mixer, and this is impossible if the head is integral with the mixer and is difficult if a tool is required to make the change from one head to another.
It would be advantageous to have a quickly disconnectable and reconnectable coupling which could be used to transmit high speed reciprocating rotary motion in a device such as a laboratory mixer. It would further be advantageous if this coupling were structured to damp and withstand torsional vibrations and provide a positive lock between the two coupled parts.